What Is a Pillow Packaging Machine?
Pillow packaging machines are used to package food, pharmaceuticals, machine parts, and other products.
It is called “pillow packaging” because the packaging form is shaped like a “pillow,” and it is suitable for high-speed mass packaging.
It can be filled with gas when packaging products, which slows down the speed of product deterioration.
Pillow packaging is not vacuumed sealable or aseptic and is unsuitable for heat-sensitive products because heat is applied during sealing.
Other types of packaging machines, such as shrink seal (heat shrink) packaging machines, small box packaging machines, and vacuum packaging machines, can also be used, depending on the product to be packaged.
Applications of Pillow Packaging Machines
Pillow wrapping machines are mainly used in the food industry and for bulk packaging of pharmaceuticals.
There are also packaging machines suitable for packaging pharmaceuticals, and each zone of machine is divided into separate zones.
Vertical pillow wrapping machines are not suitable for products that may be damaged if the product is dropped into the film from the top.
It is suitable for packaging flour, drinking water, mayonnaise, snacks, bean sprouts, machine parts, etc.
It can also be used for confectioneries individually packaged in a continuous vertical line and with gussets on the sides and bottom.
Horizontal pillow wrapping machines can pack tray containers, ice cream, chocolate, dried noodles, vegetables, toys, stationery, and pharmaceuticals in bulk but are not suitable for powders, granules, or liquids.
Horizontal pillow wrapping machines can be further classified into two types: “forward pillow wrapping machines,” in which the back seal is below the product, and “reverse pillow wrapping machines,” in which the seal is above the product.
Principle of Pillow Wrapping Machine
1. Vertical Pillow Wrapping Machine
The film is made into a tube, the overlapping parts are sealed, the product is filled from the top, and the top is sealed horizontally and separated.
Various functions can be added to the pillow wrapping machine, such as gas filling, gusset creation, film misalignment correction, product bite prevention, and sensor to prevent empty wrapping.
2. Horizontal Pillow Wrapping Machine: Positive Pillow Wrapping Machine
The film is fed from the top of the product and wrapped from the top to form a cylinder, and the overlapped portions are sealed. This machine is suitable for wrapping products on trays, products of a certain shape, and lightweight products. 3.
3. Horizontal Pillow Wrapping Machine: Reverse Pillow Wrapping Machine
The film is fed from the bottom of the machine, and the product is wrapped from the bottom to form a cylinder, and the overlapped portions are sealed.
Since the seal is on top of the product, it is easy to check for roll-in and is better suited for wrapping heavy products than regular pillow wrapping. Since the product is placed on top of the film, it is possible to wrap moist or long vegetables, and the conveyor is less contaminated.
Other Pillow Packaging Machine Information
The trouble with Pillow Packaging Machines
One trouble that can occur when working with a pillow-wrapping machine is film snaking. The cause may be a problem with the film or with the wrapping machine, and countermeasures must be taken according to the cause each time.
Typical causes and countermeasures for film snaking are as follows:
- If the Film is Too Thick or Too Thin: Installing a guide on the roller part of the wrapping machine or strengthening the brake on the take-up may improve the problem. Replacing the take-up is another solution.
- If the Film is Too Slippery: Installing guides on the packaging machine or wrapping the rollers with non-slip tape may be a solution.
- If the Film is Too Slippery: Powder dusting can be effective.
- Uneven Printing: Adjusting the roll stiffness may help.
- If the Installation or Rotation of the Wrapping Machine Rollers is Distorted: The rollers of the wrapping machine need to be adjusted.
Pillow wrapping machine film
In a pillow-wrapping machine, a sheet of film is sealed back-to-back and wrapped into a tube. To avoid seal failure, the appropriate sealing temperature must be selected based on the characteristics of each film material. There are various types of films used for packaging.
Typical film materials and characteristics are as follows:
1. Low-density Polyethylene (LDPE)
LDPE has excellent water resistance, acid/alkali resistance, heat sealability, and impact resistance. On the other hand, it tends to be inferior in organic solvent resistance and heat resistance.
2. Non-oriented Polypropylene (CPP)
Compared to LDPE, CPP has superior moisture resistance and transparency. On the other hand, it tends to be inferior to LDPE in flexibility and impact resistance.
3. Biaxially Oriented Polypropylene (OPP)
This is a film processed by stretching CPP film; it is less stretchable than CPP and has superior tensile strength, moisture resistance, and transparency. On the other hand, OPP-based films have a narrower temperature range and tend to shrink more easily.
4. Polyvinylidene Chloride-coated OPP (KOP)
This film is an OPP film coated with polyvinylidene chloride. It has excellent moisture-proofing, gas-blocking, and aroma-retaining properties.
5. Polyester (PET)
This film is made by biaxially stretching PET resin to provide strength and heat resistance. It is inferior in gas barrier properties, moisture retention, and impact resistance but is strong, has excellent heat/cold resistance, and has aroma retention properties.